Genetic transformation of Pseudochoricystis ellipsoidea, an aliphatic hydrocarbon-producing green alga

Abstract

Pseudochoricystis ellipsoidea is a recently isolated unicellular green alga, which is classified within the family Trebouxiophyceae. This alga has a unique ability to synthesize and accumulate intracellularly a significant amount of aliphatic hydrocarbons. To elucidate molecular mechanisms of the hydrocarbon production in this organism, the development of genetic methods including DNA transformation methods are important. Towards the goal, we constructed several plasmids in which neomycin phosphotransferase II-encoding G418-resistant gene (nptII) is flanked by a P. ellipsoidea-derived promoter and terminator. These plasmids were introduced into P. ellipsoidea cells through particle-gun bombardment, and transformants were screened among G418-resistant cells by PCR amplification of plasmid-borne genes. Southern blot analysis demonstrated that the exogenous DNA was integrated into the genome of the transformants. Furthermore, the expression of nptII was confirmed at the transcript and protein levels by RT-PCR and immunoblot analyses, respectively. These results clearly indicated that a genetic transformation system was successfully established for P. ellipsoidea.

Hydrothermal microwave processing of microalgae as a pre-treatment and extraction technique for bio-fuels and bio-products

“…Chlorogloeopsis fritschii (C. fritschii) was grown by the Plymouth Marine Laboratory, UK. The Pseudochoricystis ellipsoidea strain (P. ellipsoidea) was isolated by the DENSO CORPORATION, Japan and has the unique ability to synthesize and accumulate aliphatic hydrocarbons (Imamura et al, 2012). All three strains were freeze-dried before use.…”

Genetic Transformation of Tribonema minus, a Eukaryotic Filamentous Oleaginous Yellow-Green Alga

“…Transformation was achieved successfully under only two lower pressure conditions of 450 and 900 psi. The effective pressures were lower than those used in the genetic transformation of a unicellular green microalgae Pseudochoricystis ellipsoidea, the bombardment of which can achieve success from 900 to 1550 psi [33]. This might be related to the loose degree of filaments and gives fundamental manipulation parameters for the bombardment of filamentous microalgae.…”

Energy conservation in photosynthetic microorganisms

“…It produces triterpenoid botryococcenes, a potential fuel molecule that requires minimal refining (Metzger and Largeau, 2005). Pseudochoricystis produces hydrocarbons of shorter carbon chains, such as heptadecene, heptadecane and eicosadienes as major hydrocarbons, and genetic engineering is applicable for this strain (Satoh et al, 2010;Imamura et al, 2012). Emiliania huxleyii and Gephyrocapsa oceanica, marine planktonic algae, produce normal alkenones (C 11 to C 35 ) (Ono et al, 2009).…”